It is common practice to supply gas to containers for beer or soda to maintain a pressure for causing discharge of beer or soda from the container when a faucet is opened; and in taverns there are often numerous beer kegs supplied with such pressure from a manifold. Similar installations are used for taking gas at high pressure, as from a cylinder, and delivering the gas at reduced pressure for various operations. It is also common practice to install pressure relief valves in supply lines so that the pressure will be vented to the atmosphere in the event that it rises above a predetermined maximum pressure. Pressure regulators for liquids are also provided with pressure relief valves.
This invention will be described in connection with a regulator for supplying gas to beer kegs, as the preferred embodiment, but it will be understood that it can be used for controlling flow of any fluid where the installation requires the protection of a pressure relief valve, commonly referred to as a "safety valve," and it is desirable to shut off flow of the fluid to the place of use whenever there is a substantial presure rise that operates the safety valve.
Accidents and unusual conditions sometimes cause the pressure to build up in a regulator faster than the relief valve can vent the pressure. There are various safety devices which can be used to stop all flow through a pipe if the rate of flow becomes excessive, and there are other safety controls; but the purpose of the present invention is to modify a pressure regulator in a simple and inexpensive way so as to protect piping, manifolds, hoses and other apparatus, on the downstream side, from being exposed to excessive pressure when the safety valve of the pressure regulator is unable to vent the gas fast enough to relieve the pressure.
This invention installs a safety shut-off valve which automatically closes the reduced pressure delivery line from the regulator whenever the relief valve opens and regardless of whether the relief valve is capable of venting the excess pressure rapidly enough to prevent any build-up substantially higher than that for which the pressure-relief valve is loaded.
Other objects, features and advantages of the invention will appear or be pointed out as the description proceeds.